They say it takes a village to raise a child. In the retail world, it takes a village to raise an idiot. And I have worked with plenty of their offspring.
Co-workers can be a blessing in disguise, or your worst nightmare. I have worked with some who have changed my life (but not always for the better) and with some who make me hate my job. Some I'd like to forget, if only I could erase parts of my brain.
It's pretty easy to categorize your co-workers. They are "fun", "hard-working", "lazy", "smart", etc. Count your blessings if you get a hard-worker with a super personality... they are few and far between. 
I bet you can name a few co-workers who only want to talk about themselves. Kinda makes you want to chop your ears off, doesn't it? How 'bout the "Debbie Downer" of the group... bet you know someone who has that dark cloud overhead 24/7. And what about that lazy slug who thinks the world owes him something for doing nothing...
My point is: take a few moments and ponder your past. There are all types of people in the workplace. I'm sure the stupid ones outnumber the smart ones. I think they breed faster.